JPS5931213B2 - How to bond a semiconductor wafer to a lap surface plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of bonding a semiconductor wafer to a lapping surface plate in order to adjust the thickness of a semiconductor wafer on which a large number of semiconductor elements are fabricated.

Generally, when manufacturing semiconductor devices, as shown in FIG. It is normal to get

By the way, it is desirable to finish the semiconductor element 2 to a thickness of about 150μ, but in order to prevent damage during the heat treatment or chemical treatment process during the formation of the semiconductor element 2 in the wafer 1, it is usually finished with a thickness of 300μ or more. Using a wafer with a thickness of 1,
After the semiconductor element 2 is formed, the unnecessary portion 1a of the back surface of the wafer 1 is usually removed to obtain the required thickness of 150 μm. Since this scraping process is performed by lapping, it is usually called back lapping. The conventional method of bonding a wafer to a lap surface plate for performing such backlapping is as shown in FIG. After the surface of the wafer 1 was brought into close contact with this adhesive surface, the wafer 1 was fixed on the lapping surface plate 4 by heat-treating the surface. The back side of the wafer 1 fixed to the lapping platen 4 with the adhesive 6 in the manner described above is rubbed against the lapping plate and lapped to a predetermined size.

However, in the above method, not only does it take a lot of man-hours to apply the adhesive 6 to the lapping surface plate 4 one by one, but also the surface wiring portion 3 There is a risk of damage due to direct contact with the hard lap surface plate 4. J This invention was made in view of the above-mentioned points, and a sheet made of cellulose impregnated with a thermoplastic adhesive is interposed between a lap surface plate and a semiconductor wafer and bonded under heat, thereby achieving lap fixation. This reduces the number of steps needed to bond the wafer to the board, and also prevents damage to the wiring surface during bonding.

An embodiment of the present invention will be described below with reference to FIG. First, an adhesive sheet T made of cellulose and impregnated with a thermoplastic adhesive is placed on the adhesive surface of the lap surface plate 4, and the surface of the wafer 1 on which the electrodes are formed is placed on top of it so that it is in close contact with the adhesive sheet 7. , this is pressed with a heated weight 8.

Then, the thermoplastic adhesive impregnated into the adhesive sheet T is eluted to both sides of the wafer 1 and the lap platen 4, and the wafer 1 is bonded to the lap platen 4 through the adhesive sheet 7.
Thereafter, the weight 8 is removed and the eluted adhesive 9 is cooled together with the wafer 1 and the lap surface plate 4, and the wafer 1
is firmly adhered to the lap surface plate 4. The wafer 1 bonded in this manner is rubbed against a lapping machine in the same manner as in the prior art, and a predetermined back lapping Bj is performed. As described above, according to the method of the present invention, it is possible to reduce the number of man-hours required to apply adhesive to the surface of the lap surface plate unlike the conventional method, and it is also possible to reduce the number of steps required to apply adhesive to the surface of the lap surface plate, which is required in the conventional method. To prevent damage to the wiring surface of B3
There is an effect that can be achieved.

In the above-described embodiments, a wafer in which transistors are formed is used as an example of a wafer to be back-clapped, but the same effect can be obtained even if the present invention is suitable for back-clapping a wafer in which bipolar ICs or MOS Cs are formed.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a semiconductor wafer in which a large number of transistors are fabricated, FIG. 2 is a sectional view showing a conventional method, and FIG. 3 is a sectional view showing an embodiment of the present invention. In the figure, 1 is a semiconductor wafer, 4 is a lap surface plate, 7 is an adhesive sheet, 8 is a weight, and 9 is a thermoplastic adhesive.

Claims (1)

[Claims] 1. A semiconductor wafer is placed on a lapping platen via an adhesive sheet made of cellulose and impregnated with a thermoplastic adhesive, and then the semiconductor wafer is heated and pressed against the lapping platen. A method of adhering semiconductor wafers to a lap surface plate.